The estimate is based on a new survey technique developed by researchers at the Johns Hopkins University Bloomberg School of Public Health to help public health officials determine the amount of resources, services, and treatment necessary to respond to the opioid epidemic efficiently and at the right scale.

Cabell County, with a population of 94,958, has been particularly hard hit by the opioid epidemic: it saw 1,831 overdoses in 2017, 152 of which were fatal. Like other rural communities affected by the opioid crisis, Cabell County has been in dire need of a means to accurately estimate the number of people who inject drugs in order to prevent deaths and provide lifesaving drug treatment resources.

Researchers have made their population estimation tool free for download

"By understanding the size and characteristics of the populations in need, rural communities can tailor response strategies and begin turning the tide on the opioid crisis," said lead researcher Sean Allen, assistant scientist in the Bloomberg School's Department of Health, Behavior, and Society. "This research demonstrates that rural communities can leverage innovative population-estimation methods to better understand population-level needs for services among people who inject drugs."

For the study, researchers adapted the capture-recapture method of population estimation, a technique that involves collecting data in two phases and estimating the size of a population by calculating the amount of overlap between the two phases.

Researchers worked with the Cabell-Huntington Health Department to conduct nearly 800 surveys, estimating that 1,857 people had injected drugs in the last six months. In addition to determining the size of that population, the team found that the majority of them are white (83.4 percent), male (59.5 percent), and under age 40 (70.9 percent). Their intravenous drugs of choice are heroin (82.0 percent), crystal methamphetamine (71.0 percent), and fentanyl (56.3 percent). The team also identified socioeconomic traits among the population: 66 percent are unemployed, and 64.3 percent report going to bed hungry at least once a week.

Importantly, the team also identified opportunities for public health officials to assist those in need: 74.3 percent reported they had attempted to stop using drugs, and 66 percent reported accessing sterile injection equipment at a harm reduction program.

Michael Kilkenny, physician director of the Cabell-Huntington Health Department, says the department has a comprehensive harm-reduction program that provides overdose prevention resources, drug treatment referrals, and sterile injection equipment. But with 20 percent of the state's total overdoses in 2017 occurring in Cabell County alone, the department's efforts have not been enough.

"We knew what we'd been doing for years was not working," he said. "We knew we could not arrest everybody found using drugs."

The numbers help officials understand the prevalence of drug use in their community and determine the need for essential public health services, including drug treatment and overdose prevention resources.

"Cabell County may be deeply affected by the opioid crisis, but the community is resilient and making significant progress," Allen said. "With specific information about the population of people who inject drugs, the county is able to scale its services for the need."